Fuel metering and pumping device



Sept. 27, 1960 A. G. DE CLAIRE, JR 2,954,147

FUEL METERING AND PUMPING DEVICE Filed June 17. 1957 g E E 9 F5 8 T. H /A w \\\\\wr\\\\\ INVENTOR ALTON e. DeCLAlRE Jr.

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ATTORNEYS Unite Patented Sept. 27, 1 960 "2,954,147 FUEL METERING AND PUMPING DEVICE Alton G. De Claire, Jr., Harper Woods, Mich., assignor to Holley Carburetor Company, Van Dyke, Mich., a corporation of Michigan Filed June 17, 1957, Ser. No. 665,964

2 Claims. (Cl. 222250) improved fuel metering and pumping device characterized by its relatively low leakage, by the reduction of forces applied to mechanical parts of the structure, and by the avoidance of backfires caused by starving a cylinder dur-- ing acceleration.

More specifically, it is an object of the present invention to provide a fuel metering and pumping device including a metering and pumping shuttle type piston movable between a fixed and an adjustable abutment in which the adjustable abutment is of minimum size to occupy a minimum of volume within a pumping cylinder so that its movement causes a minimum of change in volume thereof.

Other objects and features of the invention will become apparentas the description proceeds, especially when taken -in conjunction with the -accompanyingdrawing, illustrating preferred embodiments of the invention, where- Figure 1 is a diagrammatic sectional view through a pumping and metering device as employed prior to the present invention.

Figure 2 is an enlarged fragmentary sectional view of a portion of the structure of Figure 1 incorporating the improvements of the present invention.

In Figure 1 there is illustrated a fuel metering and pumping device designed for use in a fuel injection system. This device is substantially like that illustrated in Downing Patent 2,731,175. For completeness the operation of the system will be briefly reviewed.

Thedevice comprises a support 10 having an inlet passage 12 and a plurality of axially and circumferentially or angularly spaced outlet passages of which 14 and 16 are but two. Fixed within the support 10 is a sleeve 18 having axially spaced inlet passages 20 and 22 both of which communicate at times with the inlet passage 12, and having outlet passages 24 and 26 communicating respectively with passages 14 and 16. Rotatable within the sleeve 18 is a cylinder or tubular rotor 28 having a first passage 30 adapted to register alternately with inlet passage 20 and outlet passage 24, and a second passage 32 adapted to register alternately with inlet passage 22 and outlet passage 26. Mounted for reciprocating movement in the cylinder 28 is a shuttle piston 34 the piston being movable between a fixed abutment 36 and an-adjustable abutment 38.

With the parts in the position illustrated in Figure 1, high pressure fuel is being admitted through passages "12, 20 and 30 into the cylinder 28 above the movable piston 34. The pressure of the fuel thus admitted forces the piston 34 downwardly and fuel is expelled through the passages 32, 26 and 16 to an internal combustion engine. Fuel being admitted above the piston 34 is being metered in quantity, dependent upon the spacing between the abutments 36 and 38. Further rotation of the cylinder 28 interrupts communication between the fuel inlet 12 and the cylinder above the piston, and establishes communication through the passages 22 and 32 to the space below the piston. This results in upward movement of the piston, expelling a metered charge of fuel through the passages 30, 24 and 14 to the engine.

The position of the adjustable abutment 38 is determined in accordance with a number of variable conditions or manually. As illustrated in Figure 1,'the. adjustable abutment 38 includes a portion '40 engageable with the inclined surface 42 of a carriage 44movable along an adjustable rail 46. The carriage 44 includes rollers 48 and is connected by a link 50 to a piston 52 movable in a cylinder 54 against a compression spring 56. The interior of the cylinder 54 is subjected to the reduced pressure existing within the engine manifold and accordingly, the carriage 44 is positioned by means responsive to manifold pressure or engine load. Carriage 44 thus constitutes a continuously movable abutment member. v

Additional means are provided for effecting adjustment of the fuel metering and this comprises a lever 58 pivoted as indicated at 60 and having an arm 62 pivoted to the rail 46 as indicated at 64. The other end of the rail is supported by a link 66 pivoted at 67 and 68.

Suitable means may be provided for moving the lever 58 and this means may be responsive to engine temperature, engine or vehicle speed, or other conditions the specific nature of which does-not enter into the present invention. p

It is contemplated that the system disclosed herein shall operate to supply fuel adjacent the intake valve of each cylinder of the internal combustion engine at relatively high pressure as for example on the order of 100 ,p.s.i. Accordingly, fuel is delivered to the inlet passage'12 at approximately this pressure. For this purpose the fuel will be supplied to the meteringand pumping device illustrated herein by a suitable fuel pump such for example as an electrically operated fuel pump which may be energized at or before operation of the engine starter.

From an inspection of Figure 1 it will be observed that the fuel above the piston 34 acts on a relatively large area of the adjustable abutment 38, this area being in effect equal to the cross-sectional area of the piston. In a practical embodiment of the invention the force developed by fuel under pressure within the cylinder and thus transmitted to the carriage 44, rail 46 and associated structure, may be several pounds in total. This in itself is undesirable. In addition, movement of the movable abutment 38 in the cylinder requires at least nominal clearance and necessarily results in some leakage of fuel past the outer surfaces of the movable abutment. The present construction, as will subsequently appear, substantially reduces oil leakage.

Finally, the most important advantage attained by the modified construction illustrated in Figure 2 is in the preventing of backfires due to starving a cylinder during acceleration.

Referring now to Figure 2, the present invention comprises replacing the adjustable abutment 38 of Figure 1 with a sealed guide sleeve 7 0, this sleeve as illustrated being retained in the upper end of the cylinder 28 by an annular flanged retainer 72. Extending through the guide sleeve 70 is a relatively small cylindrical opening 7 4 which receives a pin 76 constituting the movable abutment which determines upward movement of the shuttle piston 34. Except for parts 70, 72, and 76, the parts shown in Figure 2 are the same parts identified by like reference characters in Figure 1.

By this arrangement a cross-sectional area of the movable portion of the adjustable abutment is reduced to a small fraction of the area of the cylindrical opening'in ,the cylinder 28. Thus, the force acting through the pin 76 on the structure thereabove is reduced and at the same time the leakage around the movable pin 76 is reduced to a fraction of that present in the old construction. In a practical design the force applied through the adjustable abutment to the adjusting mechanism therefor was reduced from several pounds to a fraction of a pound.

A very important improvement resulting from the substitution of the sleeve 70 and reduced pin abutment 76 is in the reduction of variation of volume above the piston 34 when the pin 76 is retracted during acceleration to produce 'an increase in the charge of fuel delivered to a cylinder of the engine. It will be recalled that each stroke of the shuttle piston may be regarded as a metering stroke at one side of the piston which takes place during the pumping stroke effected at the other side of the piston. When the carriage 44 is moved suddenly in order to increase the fuel flow for acceleration, the movable abutments move outwardly allowing the shuttle piston 34 to move farther. However, with this longer stroke of shuttle piston 34, more fuel will not be forced out of the pumping device until the volume of space emptied by outward movement of the adjustable abutment 38 or 76 is filled with fuel. When accelerating an engine with this control this means that a lean fuel mixture will be delivered to one cylinder and a backfire could occur. With the relatively small change in volume caused by withdrawal of pin 76;, this does not happen.

The present invention, while it involves a relatively simple modification of the structure, nevertheless results in important operating advantages and in increased life due to the reduced wear of the parts.

The drawing and the foregoing specification constitute a description of the improved fuel metering and pumping device in such full, clear, concise and exact'terms as to enable any person skilled in the art to practice the invention, the scope of which is indicated by the appended claims.

What I claim as my invention is:

1. A fuel metering and pumping device comprising a stationary sleeve having axially and angularly spaced radially extending inlet and outlet passages, a tubular rotor having an axially extending clindrical opening therethrough and axially spaced radially extending passages each of which communicates with an inlet and an outlet passage of said sleeve during rotation of said rotor, a shuttle type piston movable axially in said rotor between the axially spaced passages of said rotor, a fixed abutment at one end of said rotor engageable with said piston, a guide sleeve fixedly secured in the other end of said rotor, condition reponsive means including a continuously movable abutment member located beyond the end of said rotor in which said guide sleeve is located, said guide sleeve having an elongated opening therethrough in alignment with the cylindrical opening through said rotor, the

cross-sectional area of the opening through said sleeve being substantially less than that of the cylindrical opening through said tubular rotor, and an elongated abutment pin freely slidable in said opening and having an inner end exposed to fluid pressure within the cylindrical opening in said rotor and engageable with said piston to limit movement thereof in one direction and having its other end engaged with said abutment member for continuous adjustment thereby, the eflfective end area of said pin exposed to fluid pressure Within said rotor being substantially less than the cross-sectional area of said cylindrical open- 2. A device as defined in claim 1 in which the effective end area of said pin exposed to fluid pressure within said rotor being less than one-quarter of the cross-sectional area of said cylindrical opening.

References Cited in the file of this patent UNITED STATES PATENTS 1,299,001 Moore Apr. 1, 1919 1,482,467 Harrington Y Feb. 5, 1924 2,731,175 Downing Jan. 17, 1956 FOREIGN PATENTS 727,545 Great Britain Apr. 6, 1955 

